Numerical experiments on low-energy ion scattering at a surface containing adsorbed impurity atoms

The energy distributions of Cs⁺ and W⁺ ions scattered, respectively, at Mo and W single crystals, the surfaces of which contain adsorbed oxygen, nitrogen, and cesium atoms, are calculated via the molecular dynamics method. It is demonstrated that the energy spectra are sensitive to the impurity atoms of a surface. When compared with the energy distributions corresponding to a pure surface, even a partial monolayer of these atoms can modify their shape. A peak in the scattered-ion intensity is commonly shifted to the lowerenergy region if the adsorbate is light and to higher energies if the adsorbate is heavy.